Electric supply rail with collecting carriage

ABSTRACT

The invention concerns a power supply rail ( 1 ) in the form of a profiled section ( 3 ), wherein are longitudinally arranged electrically conductive tracks ( 4 ), which co-operate with current collector shoes ( 11 ) borne by the collector carriage ( 2 ), guided by the rail ( 1 ), said carriage being connected to a mobile element to be electrically powered. Inside the rail ( 1 ) is provided a continuous position and/or displacement detecting track ( 17 ), which co-operates with a detector ( 18 ) borne by the part ( 7 ) of the collector carriage ( 2 ) housed inside the rail ( 1 ). The detector is linked to signal processing means ( 23 ). The instantaneous position and/or the displacement of the associated mobile element can thus be controlled.

The present invention relates to an electric supply rail, shaped as aprofiled section and inside which there are longitudinally arrangedelectrically conducting tracks, this rail guiding a current-collectingcarriage connected to a moving element that is to be electricallypowered, this carriage being provided with current-collecting wipers,coming into contact with the conducting tracks of the rail, and meansbeing provided for monitoring the position of the moving element.

In certain industries it is necessary to be able to electrically powerelements, assemblies or moving apparatus, for example electricallyoperated tools, that are to be used at a variable location within acertain space. To do this, one known technical solution is to use anelectric supply rail with a collecting carriage.

The supply rail, usually arranged horizontally, consists of a profiledsection made of electrically Insulating material, closed on all sidesexcept for a longitudinal slot made in its bottom face. Arranged insidethe profiled section are electrically conducting tracks, particularlyones made of copper, in varying number, these conducting tracks beingdistributed over the internal side walls and/or the upper wall of theprofiled section.

The current-collecting carriage comprises an upper part housed insidethe rail, and a lower part situated under the rail, these two partsbeing connected by an intermediate part which passes through thelongitudinal slot in the profiled section. The part of the carriage thatis housed inside the rail may or may not be provided with rollers whichroll along guide tracks formed inside the profiled section. This part ofthe carriage also carries current-collecting wipers in sliding contactwith the conducting tracks of the rail. The part of the collectingcarriage situated under the rail serves as an outlet for an electricalpower supply lead leading toward the mobile element that is to bepowered, which “follows” the carriage in its movements.

Hence, regardless of its position, the collecting carriage collectselectrical current and conveys the current to the associated movingelement. The rail may have straight and/or curved portions and maypossibly form a closed loop, it being possible for current to becollected from any point along the rail.

In some applications, the mobile element to be electrically powered bythe above-described device is suspended from another carriage that canrun along a runway track parallel to the electric supply rail. Theposition and/or the displacement of the moving element that is to bepowered then correspond to the position and/or to the displacement ofthe current-collecting carriage.

In the latter case, there is a need to determine, at every moment, theposition occupied by the moving element, whether this be for safetyreasons or in order to control certain actions of this moving element inparticular positions. This currently entails the addition of specialposition-monitoring equipment for monitoring the position of said movingelement.

It will also be noted that the customary devices used to monitor theposition and/or the displacement of moving bodies guided along rails,particularly suspended carriages moving along rails that also provide anelectrical power supply are:

-   -   either devices that can be applied only to motorized carriages        (see, for example, document GB 2 277 069);    -   or devices which detect only the passage of carriages through        certain particular points (see, for example, documents U.S. Pat.        No. 4,700,024 and JP 60154923);    -   or devices which detect only the presence of the carriages        within areas of greater or lesser extent, particularly to avoid        collisions between carriages (see, for example, document U.S.        Pat. No. 4,688,487).

Thus, the prior art does not propose any simple solution for the“continuous” detection of the precise position of an unmotorizedcarriage, particularly of a current-collecting carriage connected toanother moving element.

The present invention aims to provide a simpler and more economicalsolution making it possible continuously to detect the position and/orthe displacement of the moving element, associated with thecurrent-collecting carriage, with a view to transmitting the positionand/or displacement information to any command-control device.

To this end, the object of the invention is essentially an electricsupply rail with a collecting carriage, of the kind concerned here, inwhich, in order to determine the instantaneous position occupied by themoving element there is provided, inside the profiled section that formsthe supply rail, a position and/or displacement detection track runningcontinuously along the length of the rail and collaborating with adetector borne by part of the collecting carriage which part is housedinside said rail, the detector being connected to signal processingmeans for processing the signals originating from this detector.

According to a preferred embodiment of the invention, the positionand/or displacement detection track consists of a continuous toothedelement toothed with a regular pitch, particularly a toothed belt, fixedlongitudinally inside the rail, while the detector, borne by thecollecting carriage, is a detector of optical type, for exampleinvolving optical fibers, which lies facing the toothed element.

Thus, the invention provides means for detecting the position and/or thedisplacement of the collecting carriage, and therefore of the movingelement associated with this carriage and powered electrically thereby,which are fully incorporated into the supply rail and into thecollecting carriage, and which therefore do not require any additionalapparatus. These means allow the position to be detected at every pointand at every moment. The positions and displacements of the movingelement can thus be perfectly monitored.

In addition, in the preferred embodiment of the invention using atoothed belt, use can be had of a means that is particularly economical,but sufficiently precise, this toothed element being of indefinitelength and able, where necessary, to follow a curved path. The toothedelement, such as a toothed belt, may be housed in an interiorlongitudinal groove of the profiled section that constitutes the rail,this groove being similar to the other longitudinal grooves belonging tothis profiled section, in a usual manner, that accommodates theconducting tracks, thus affording a simple embodiment.

However, in an alternative form of the invention, the position and/ordisplacement detection track consists of a magnetic stripe or a strip,fixed longitudinally inside the rail and collaborating with a detectorof magnetic type.

According to another alternative form, the position and/or displacementdetection track consists of a graduated stripe, fixed longitudinallyinside the rail and collaborating with a detector of optical type.

According to one advantageous embodiment, the signal processing meansfor processing the signals originating from the detector borne by thecollecting carriage comprise an electronic processing unit borne by thecollecting carriage itself. In addition, this “on-board” processing unitmay communicate, via the conducting tracks of the rail itself, with afixed control box which carries out additional information-processingoperations, in order to make this information usable, thus avoiding theneed to add a wire connection or a radio link.

In practice, the device makes it possible to detect the position of thecollecting carriage, recognize its direction of travel, and measure itsspeed of travel.

The invention will be better understood using the description whichfollows, with reference to the attached schematic drawing, which, by wayof example, depicts one embodiment of this electric supply rail withcollecting carriage:

FIG. 1 is an overall perspective view of a supply rail, with partialcutaway, and of the collecting carriage guided by this rail;

FIG. 2 is a view in cross section of the rail and of the carriage;

FIG. 3 is a view in longitudinal section of the carriage, and of thecorresponding region of the rail:

FIG. 4 is a block diagram of the device as a whole, with the associatedmoving element;

FIG. 5 shows detail of the detector, and the associated electronicboard.

In the figures, the reference numeral 1 denotes, in its entirety, anelectric supply rail while the reference numeral 2 denotes, overall, acurrent-collecting carriage guided along the rail 1.

The electric supply rail 1 consists of an insulating profiled section 3,inside which electrically conducting tracks 4 are arrangedlongitudinally.

The insulating profiled section 3 has a cross section of rectangularshape, with two lateral faces, a top face and a bottom face, as shown inFIGS. 1 and 2. A longitudinal slot 5 is formed in the bottom face of theprofiled section 3.

The conducting tracks 4 comprise, in the example illustrated, twosuperposed conducting tracks 4 placed on one lateral face of theprofiled section 3, two other superposed conducting tracks 4 placed onthe other lateral face of the profiled section 3, and a last conductingtrack 4 placed on the top face of the profiled section 3. These fiveconducting tracks 4 consist in particular of copper strips, housed ininternal longitudinal grooves 6 belonging to the profiled section 3.

The electric supply rail 1 is fixed to, and particularly hung from, asupport structure, by appropriate means such as hangers, not depicted.

The current-collecting carriage 2 comprises an upper part 7 housedinside the rail 1, and a lower part 8 situated under the rail 1; thesetwo parts 7 and 8 are joined together by an intermediate part 9 whichpasses vertically through the longitudinal slot 5 in the profiledsection 3.

The upper part 7 of the carriage 2 is provided with rollers 10 whichroll along guide tracks formed inside the profiled section 3. This upperpart 7 also bears current-collecting wipers 11 associated with thevarious conducting tracks 4 of the rail 1. In the example illustrated,each wiper 11 is made up of two copper wipers 12, mounted at the ends ofa metal leaf spring 13 fixed, by its central part, to the body of theupper part 7 of the carriage 2.

The lower part 8 of the carriage 2 is in the form of a box, from whichthere departs an electrical power supply lead 14 which leads to a movingelement, depicted schematically as 15 in FIG. 4, associated with thecarriage 2.

In the region of its longitudinal slot 5, the profiled section 3 bearstwo sealing lips 16, pressing one against each side of the intermediatepart 9 of the carriage 2.

There is also provided, within the profiled section 3 that constitutesthe electric supply rail 1, a position and/or displacement detectiontrack consisting of a toothed belt 17. The track thus formedcollaborates with a detector 18 of optical type, borne by the upper part7 of the current-collecting carriage 2.

The toothed belt 17, running in the longitudinal direction of the rail1, is housed and held in an interior longitudinal groove 19 of theprofiled section 3. It lies along a side wall of the profiled section 3,between the two conducting tracks 4 borne by the same wall. The notchesor teeth 20 of the toothed belt 17 follow on from one another with aconstant pitch P, for example of 1.25 mm—see also FIG. 5.

The optical detector 18 is borne by the body of the upper part 7 of thecarriage 2, so that it lies facing the toothed belt 17. This is adetector involving optical fibers 21 and 22, which is connected to an“on-board” electronic board 23, this electronic board 23 being housed inthe box-shaped lower part 8 of the carriage 2.

The electronic board 23 comprises several functional subassemblies asdepicted schematically in FIG. 5:

-   -   An optical processing unit 24 provides analog detection of the        notches or teeth 20 (rising fronts) of the belt 17. It will be        noted that this unit 24 also, via an additional device 25,        detects the origin point of a length of rail 1, so as to provide        re-zeroing, for example every four meters, so as to avoid any        undesirable drift in the detection of the position.    -   An information processing unit 26 counts, processes and converts        the rising fronts and calculates the position, the direction of        travel and the speed of travel of the carriage 2.    -   A last unit 27, acting as a transmitter, electrically matches        the signals to allow them to be transmitted in digital form,        along the conducting tracks 4 of the rail 1, to a fixed control        box 28.

The control box 28, also visible in FIG. 4, which thus receives theinformation transmitted by the power conductors of the rail 1, performsan additional processing operation on this information to make it usableafter processing. In particular, the signals received are processed,within the control box 28, so as to deliver, on an output 29, a signalof the “incremental encoder” type and, on another output 30, speedinformation in analog form (an electrical voltage proportional to thespeed).

The following would not constitute departures from the scope of theinvention as defined in the attached claims:

-   -   if modifications were made to the shape of the profiled section        of which the rail is formed and/or to the number of conducting        tracks on this rail;    -   if the toothed belt were replaced by any similar toothed element        such as a rack, or alternatively by a magnetic stripe or strip,        or a graduated stripe, collaborating with an appropriate        detector;    -   if the toothed belt or other equivalent detection track were        arranged at any position within the rail;    -   if modifications were made to the configuration of the        collecting carriage, which may have a one-piece structure        (instead of being made in several parts), it then also being        able to be a sliding carriage, with no rollers;    -   if the signals originating from the detector were processed        differently;    -   if the device were combined with any element, assembly or moving        apparatus to be electrically powered, and the position and/or        displacement of which were to be monitored.

1. An electric supply rail, shaped as a profiled section and insidewhich there are longitudinally arranged electrically conducting tracks,this rail guiding a current-collecting carriages connected to a movingelement that is to be electrically powered, the position and/or thedisplacement of which moving element correspond to the position and/ordisplacement of the current-collecting carriage, this carriage beingprovided with current-collecting wipers, coming into contact with theconducting tracks of the rail, and means being provided for monitoringthe position of the moving element, characterized in that, in order todetermine the instantaneous position occupied by the moving elementthere is provided, inside the profiled section that forms the supplyrail, a position and/or displacement detection track runningcontinuously along the length of the rail and collaborating with adetector borne by part of the collecting carriage which part is housedinside said rail, the detector being connected to signal processingmeans for processing the signals originating from this detector.
 2. Theelectric supply rail with collecting carriage as claimed in claim 1,characterized in that the position and/or displacement detection trackconsists of a continuous toothed element toothed with a regular pitch;particularly a toothed belt, fixed longitudinally inside the rail, whilethe detector, borne by the collecting carriage, is a detector of opticaltype, for example involving optical fibers, which lies facing thetoothed element.
 3. The electric supply rail with collecting carriage asclaimed in claim 2, characterized in that the toothed element, such as atoothed belt, is housed in an interior longitudinal groove of theprofiled section that constitutes the rail, this groove being similar tothe other longitudinal grooves belonging to this profiled section thataccommodate the conducting tracks.
 4. The electric supply rail withcollecting carriage as claimed in claim 1, characterized in that theposition and/or displacement detection track consists of a magneticstripe or a strip, fixed longitudinally inside the rail andcollaborating with a detector of magnetic type.
 5. The electric supplyrail with collecting carriage as claimed in claim 1, characterized inthat the position and/or displacement detection track consists of agraduated stripe, fixed longitudinally inside the rail and collaboratingwith a detector of optical type.
 6. The electric supply rail withcollecting carriage as claimed in claim 1, characterized in that thesignal processing means for processing the signals originating from thedetector borne by the collecting carriage comprise an electronicprocessing unit borne by the collecting carriage itself.
 7. The electricsupply rail with collecting carriage as claimed in claim 6,characterized in that the “on-board” processing unit communicates, viathe conducting tracks of the rail itself, with a fixed control box whichcarries out additional information-processing operations.
 8. Theelectric supply rail with collecting carriage as claimed in claim 6,characterized in that the electronic processing unit also, via anadditional device, detects the origin point of a portion of the rail soas to perform re-zeroing.
 9. The electric supply rail with collectingcarriage as claimed in claim 2, characterized in that the signalprocessing means for processing the signals originating from thedetector borne by the collecting carriage comprise an electronicprocessing unit borne by the collecting carriage itself.
 10. Theelectric supply rail with collecting carriage as claimed in claim 3,characterized in that the signal processing means for processing thesignals originating from the detector borne by the collecting carriagecomprise an electronic processing unit borne by the collecting carriageitself.
 11. The electric supply rail with collecting carriage as claimedin claim 4, characterized in that the signal processing means forprocessing the signals originating from the detector borne by thecollecting carriage comprise an electronic processing unit borne by thecollecting carriage itself.
 12. The electric supply rail with collectingcarriage as claimed in claim 5, characterized in that the signalprocessing means for processing the signals originating from thedetector borne by the collecting carriage comprise an electronicprocessing unit borne by the collecting carriage itself.
 13. Theelectric supply rail with collecting carriage as claimed in claim 7,characterized in that the electronic processing unit also, via anadditional device, detects the origin point of a portion of the rail soas to perform re-zeroing.